protected void Session_End(object sender, EventArgs e)
        {
            // Code that runs when a session ends.
            // Note: The Session_End event is raised only when the sessionstate mode
            // is set to InProc in the Web.config file. If session mode is set to StateServer
            // or SQLServer, the event is not raised.
            if (this.Context == null)
            {
                return;
            }
            UserValidator userInSession = this.Session[Sessions.GetUserValidator()] as UserValidator;

            if (userInSession != null)
            {
                AppUtility.OnUserLogout(userInSession, this.Request);
            }
        }